Geological and geochemical evolution of the Bolkardagi bauxite deposits, Karaman, Turkey: Transformation from shale to bauxite

The Bolkardagi bauxite province is located in the Tauride Belt of southern Turkey. The region hosts many lateritic- and karstic-type bauxite deposits within the Bolkardagi Unit (BU), the Namrun Tectonic Unit (NTU) and the Aladag Unit (AU). The lateritic-type deposits occur on the Upper Triassic sericite-chlorite schist of the BU, on the Lower Triassic slates, and on the Upper Triassic phyllites of the NTU. The gradual transition from the protolith to saprolite and, eventually, to bauxite is observed in the lateritic-type deposits in the field. The karstic-type deposits occur in the carbonates of the BU, the NTU and the AU and were accumulated by clastic transportation from the lateritic material. The deposits within the BU and the NTU are metamorphosed and consist mainly of diasporite, haematite, pyrophyllite, chlorite, chamosite, and anatase; the deposits within the AU are not metamorphosed and consist mainly of boehmite and kaolinite, haematite, goethite, chlorite and anatase

Geochemical/isotopic evolution of Pb-Zn deposits in the Central and Eastern Taurides, Turkey

The Central and Eastern Taurides contain numerous carbonate-hosted Pb-Zn deposits, mainly in Devonian and Permian dolomitized reefal-stramatolitic limestones, and in massive Jurassic limestones. We present and compare new fluid inclusion and isotopic data from these ore deposits, and propose for the first time a Mississippi Valley-type (MVT) mode of origin for them

Rare earth element (REE) resources of Turkey: An overview of their characteristics and origin

The Rare Earth Elements (REE) deposits and mineralization of Turkey can be divided into four types based on their geological setting and origin. First are deposits associated with carbonatite-alkaline magmatic rocks, rich in Light Rare Earth Elements (LREE). The bast known examples are the Kizilcaoren (Eskisehir) and Kuluncak (Malatya) deposits with TREE grades of 2.9% and 0.7% respectively, and typical enrichment of La-Ce. Lower grade REE mineralization at Keban (0.05% TREE) and Divrigi (0.13% TREE) is associated with abundant fluorite and all four occurrences show similar ranges for homogenization temperatures and salinities for fluid inclusions in fluorite and REE profiles. The second type are Triassic shales and the bauxites formed from them in the Bolkardagi region. Enrichment of Heavy REE (HREE) is typical and TREE grades are about 0.15% in bauxites and its protolith. These occurrences are geochemically similar to "ion adsorption type" deposits associated with lateritic clay on the weathered granitic rocks of China. Third is the placer type, represented by the canakli (Burdur) deposit which is enriched in U, Th and HREE and heavy minerals such as; magnetite, zircon and rutile and has an average grade of about 0.08% TREE. The fourth potential source of REE is phosphorites. These rocks host the world's largest resources elsewhere, however the Cretaceous Mazidag deposits in Turkey are very low grade (40ppm TREE) and clearly uneconomic. Consideration of the environmental and health issues associated with exploitation and processing of REE has identified the more favorable outcomes associated with exploitation of the ion adsorption type of deposits and justification for further evaluation of the resources and processing technologies that would enable exploitation of REE-enriched bauxites in the Bolkardagi region

Geochemical stratigraphy of the Karakaya non-sulphide Zn-Pb deposit, Hakkari, SE Turkey

The Karakaya non-sulphide Zn-Pb deposit occurs within a sequence of Middle-Upper Triassic-Jurassic carbonates. The deposit consists of three main parallel ore zones each with an average thickness of 2.5 m. The ore consists of smithsonite, hemimorphite, zincite/hydrozincite, goethite, hematite, cerussite and anglesite. This study details trace element behaviour throughout the 30 m thick sequence of the third ore zone. The average TI, As, Hg, Sb, Mo, Mn and Ba content of the associated carbonates are 13,49, 0.25, 2, 4, 2970 and 1454 ppm, respectively. These values are much higher than the average of marine carbonates (0.14,2.6, 0.04, 1.5, 2, 0.055, and 10 ppm). The average content of the TI, As, Hg, Sb, Se, Mo, Mn and Ba in the 13 ore levels of the third ore zone are 301, 3938, 15, 114, 3, 90, 5629, and 1189 ppm, respectively. The enrichment of the same trace elements in the both ore and associated carbonates suggests a repeated hydrothermal discharge into a sedimentary basin. Trace element-rich ore and carbonates imply a metal-rich pool where the TI, As, Hg, Sb and Mo precipitated at a basin scale. These trace element associations are more indicative of SEDEX-type mineralization not MVT or Irish-type Zn-Pb deposits

Mineralogy, mineral chemistry, fluid inclusion, and stable isotope investigations of the Kabaduz ore veins, Ordu, NE-Turkey

Hydrothermal vein-type deposits of the Kabaduz region (Ordu, NE-Turkey) are located in Upper Cretaceous andesitic-basaltic rocks and were formed in fault zones along NW-SE direction lines, with thicknesses varying between a few centimetres up to 2 m. The primary mineral paragenesis of the many different ore veins consists of pyrite, chalcopyrite, sphalerite, galena and tetrahedrite-tennantite, with quartz and lesser amounts of calcite and barite as gangue minerals. Electron microprobe analyses indicate that the sphalerite and tetrahedritetennantite have low Fe contents, with values less than 3.37 wt.% and 1.56 wt.%, respectively. The very low Ni and Co contents of the pyrites (<0.04 wt.%) and the Zn/Cd ratio of the sphalerite (similar to avg. 100) indicate that the hydrothermal solutions were related to felsic magmatic activity. The homogenisation temperatures and calculated salinity data vary between 180-436 C and 0.4-14.7 NaCl% eq., respectively. A well-defined negative correlation between the T-h and the salinity data suggests that meteoric water was involved in the hydrothermal solutions. Based on the measured first melting temperatures, CaCl2, MgCl2, NaCl and KCl were dominant in the fluid inclusions. The 6348 compositions of the pyrite, chalcopyrite, sphalerite, and galena mineral separates of the investigated ore veins were measured at between 2.14 and -1.47%., and the oxygen and hydrogen isotope compositions varied between 7.8-8.5%0 and -40 -57%., respectively. Based on the sulphur, oxygen and hydrogen isotope compositions, magmatic sources were confirmed for the hydrothermal solutions. Taking into account all of the above data and the granitic intrusions around the area, we concluded that younger granitic intrusions were responsible for the ore mineralisation around the Kabaduz region. (C) 2014 Elsevier B.V. All rights reserved

Mineralogical and geochemical evidence of late epithermal alteration in the Kisladag porphyry gold deposit, Usak, Western Turkey

The Kisladag porphyry gold deposit is related to Miocene intrusive and sub-volcanic rocks that resulted from an extensional tectonic regime in western Anatolia. The main lithologies of the deposit are quartz-trachytes to quartz-latites and volcanoclastic rocks intruded by sub-volcanic porphyritic rocks. Three different intrusive phases which have been identified from their age, alteration grade and mineralization (IN-1: the oldest intrusion, intense potassic alteration, IN-212A: intense clay-quartz alteration, IN-3: the youngest intrusion, weak alteration). IN-1 contains quartz, illite and kaolinite, IN-2A has quartz, adularia, illite, kaolinite and smectite. Alunite, jarosite and tourmaline increase in IN-1 and IN-2A; whereas biotite and illite increase in IN-1 and IN-2A, respectively. The volcanoclastic rocks are composed of quartz, alunite and kaolinite/halloysite indicating advanced argillic alteration. Although the microscopic data confirms potassic and phyllic alterations in IN-1 and IN-2A, mineralogical (well crystallized 1M and poorly crystallized 1 M-d illite, kaolinite/halloysite, alunite, jarosite) and geochemical (K/Ar age data for different grain-sized illite indicating late overprinting at least 5 Ma) data indicate that the early stage alteration phases were overprinted by the late stage epithermal alteration